My prior U.S. Pat. Nos. 4,842,083; 4,856,601; and 4,690,229, which are hereby incorporated by reference, are directed to drilling systems and methods providing distinct advantages. U.S. Pat. No. 4,842,083, entitled “Drill Bit Stabilizer”, is directed to a stabilizing system to stabilize the drill bit and drilling string in a down hole system, and the present invention is directed to improvements in the system and methods described therein. Although the prior system and methods provide the desired stabilization of the drill bit under most circumstances, it has been found to be desirable to minimize the actuating forces required on the wedge shaped stabilizing members in order to affect the frictional blocking action needed for radial stability. Also, it has been found to be desirable to account for high down hole drilling pressures, particularly where the stabilizing members are spring actuated, such that the drilling fluid pressure does not adversely interfere with the spring action of the stabilizing members. Blockages of various orifices or recesses in the system can also cause problems, and the present invention is directed at reducing or eliminating such possible blockages, particularly around the stabilizing members. It has also been found that under certain conditions, the bit may not be properly stabilized by the stabilizing members, such as at the beginning of a drilling operation or where no pilot hole is formed in the borehole. In such situations, it would be desirable to provide stabilization for the bit face until sufficient hole has been drilled to allow the stabilizing members to engage the bore hole wall. Thus, it would be desirable to prevent vibration damage of PDC cutting elements on the bit which can occur during the start of drilling a bore hole, or to prevent harmful axis wobble of the assembly may occur during ongoing drilling operation.
As will be shown herein, the present invention includes improved means so as to overcome the deficiencies and problems mentioned above.